define isNaN as function(n) { return n !== n; }

Note that isNan() and n !== n is not the same because isNaN() can take
non-number type values e.g. isNaN("foo") -> true
Merge branch 'gfx/fast-isNaN'
define inlinable ver. of isNaN()
close #305; native inner classes
fix "strip" optimizer for native inner classes
Merge branch 'gfx/native-inner-class'
close #209; multi in-line native definitions
resolve a todo (t/run/306)
fix a test
Merge branch 'gfx/fix-multi-ind'
releng for v0.9.50
update bootstrap compiler
fix an native inner class issue
fix native inner class (again)
Merge branch 'gfx/fix-native-inner-2'
fix jsxdoc to output inner classes
allow jsxdoc to include indent and newlines
[jsxdoc] trim description of parameters
[jsxdoc] trim description
[jsxdoc] more trim